With respect to internal combustion engine systems there remains an ever increasing need for techniques to improve fuel economy due to the cost of fuel as well as governmental regulations. At the same time, there is an increasing need for mitigation of ambient emissions of a number of pollutants including, for example, oxides of nitrogen (NOx), oxides of sulfur (SOx), particulate emissions, and hydrocarbon emissions. Internal combustion engines such as diesel engines may benefit from emissions control technologies such as oxidation catalysts, particulate filters, and selective catalytic reduction (SCR) systems to ameliorate emissions. Hybrid powertrain systems offer additional potential for reducing fuel consumption and mitigating emissions.
In pursuit of the aforementioned goals, powertrains may include increasingly complex and interdependent combinations of internal combustion engines and aftertreatment systems. The inclusion of hybrid powertrain components further increases complexity and adds interdependence. A further layer of complexity is that powertrain systems may have to meet different goals or requirements in different system applications and configurations. In many applications and configurations the system controls must cope with frequent and varying transient operating conditions, as well as longer term changes in duty cycle. For example, a commercial delivery vehicle may purposed for short haul operation in which it encounters transient states associated with city driving such as frequent acceleration and stopping along with steady state operation such as idling. This same vehicle may also be purposed for longer haul operation in which its duty cycle is nominally closer to consistent steady state (albeit a quite different type of steady state than idling) but is in fact subject to a variety of types of transients associated with changes in altitude, fuel quality variation, headwind, air temperature, grade changes, traffic flow, passing events, and/or engine braking events among others. Yet another layer of complexity is that the cost of fuel and urea solution as well as the regulation of fuel economy and emissions vary both over time and geographically.
The controls challenges for such systems are non-trivial. There is a need for control strategies and techniques which optimize multiple factors which contribute to the cost and expense of ownership and operation of such systems including, for example, consumption of fuel, consumption of reductant such as urea solution frequently utilized in SCR systems, and battery life and health, while simultaneously meeting potentially varying emissions requirements. Existing attempts to address these competing and varying goals and objectives suffer from a number of disadvantages, drawbacks, and shortcomings. Existing attempts also fail to account for manufacturing variation and aging effect of engines, aftertreatment systems, and hybrid powertrain components. There is a substantial and long-felt need for the controls techniques, apparatuses, methods and systems disclosed herein.